M24LR64-R Datasheet, PDF (25/126 Pages) STMicroelectronics – 64 Kbit EEPROM with password protection & dual interface: 400kHz I²C serial bus & ISO 18000-3 mode 1 RF protocol at 13.56MHz

M24LR64-R
System memory area
4.3
I2C_Write_Lock bit area
In the I²C mode only, it is possible to protect individual sectors against Write operations.
This feature is controlled by the I2C_Write_Lock bits stored in the 8 bytes of the
I2C_Write_Lock bit area starting from the location 2048 (see Table 13). Using these 64 bits,
it is possible to write-protect all the 64 sectors of the M24LR64-R memory.
Each bit controls the I²C write access to a specific sector as shown in Table 13. It is always
possible to unprotect a sector in the I²C mode. When an I2C_Write_Lock bit is reset to 0,
the corresponding sector is unprotected. When the bit is set to 1, the corresponding sector
is write-protected.
In I²C mode, read access to the I2C_Write_Lock bit area is always allowed. Write access
depends on the correct presentation of the I²C password.
To access the I2C_Write_Lock bit area, the device select code used for any I²C command
must have the E2 Chip Enable address at 1.
On delivery, the default value of the 8 bytes of the I2C_Write_Lock bit area is reset to 00h.
Table 13. I2C_Write_Lock bit
I²C byte address
Bits [31:24]
E2 = 1
E2 = 1
2048
2052
sectors 31-24
sectors 63-56
Bits [23:16]
sectors 23-16
sectors 55-48
Bits [15:8]
sectors 15-8
sectors 47-40
Bits [7:0]
sectors 7-0
sectors 39-32
4.4
System parameters
The M24LR64-R provides the system area required by the ISO 15693 RF protocol, as
shown in Table 14.
The first 32-bit block starting from I²C address 2304 stores the I²C password. This password
is used to activate/deactivate the write protection of the protected sector in I²C mode. At
power-on, all user memory sectors protected by the I2C_Write_Lock bits can be read but
cannot be modified. To remove the write protection, it is necessary to use the I²C Present
Password described in Figure 8. When the password is correctly presented — that is, when
all the presented bits correspond to the stored ones — it is also possible to modify the I²C
password using the I²C Write Password command described in Figure 9.
The next three 32-bit blocks store the three RF passwords. These passwords are neither
read- nor write- accessible in the I²C mode.
The next 2 bytes are used to store the AFI, at I²C location 2322, and the DSFID, at I²C
location 2323. These 2 values are used during the RF Inventory sequence. They are read-
only in the I²C mode.
The next 8 bytes, starting from location 2324, store the 64-bit UID programmed by ST on the
production line. Bytes at I²C locations 2332 to 2335 store the IC Ref and the Mem_Size data
used by the RF Get_System_Info command. The UID, Mem_Size and IC Ref values are
read-only data.
Doc ID 15170 Rev 8
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